1. BONDING

2. Bonds Between Atoms Covalent Ionic Molecular Substance Network Solids Metallic Metals Alloys

3. Ionic Bonds What is an Ionic Bond? - results from the TRANSFER of electrons from one bonding atom to another - the resulting ions are held by electrostatic forces in a 3D lattice

4. Example 1 www.mhhe.com/physsci/chemistry/animations/chang_7e_esp /bom1s2_11.swf -

5. Magnesium Oxide

6. Potassium Oxide Click for Animation

7. What are some characteristics of an ionic bond? 1. Crystalline at room temperatures 2. Have higher melting points and boiling points compared to covalent compounds 3. Conduct electrical current in molten or solution state but not in the solid state

8. Covalent Bonds What is an Covalent Bond? - results from SHARING of electrons between 2 bonding atoms. Click for animation

9. What are some characteristics of a covalent bond? 1. Weak intermolecular forces among neutral molecules 2. Have low melting points and boiling points 3. Do not conduct electrical current

10. Covalent Network Solids when atoms are bonded together covalently to form an infinite orderly array in 3 dimensions Because there are only covalent bonds, network solids are extraordinarily strong

11. Diamond Each Carbon atom bonds to 4 others Strong covalent bonds throughout High melting points and Boiling points No free electrons so does not conduct electricity.

12. Graphite Each Carbon atom is bonded to 3 others The bonding within the layers is strong covalent. The spare fourth electron of each C atom is delocalised so graphite can conduct electricity There are weak intermolecular forces of attraction between the layers.

13. Silicon Dioxide: Sand & Quartz

14. Metallic Bonding Metals normally occur as solids (high melting points) Thus, there must be strong bonds between the atoms of metals

15. Metallic Bonding Bonding in metals is different from other compounds: positive nuclei exist in a sea of delocalised electrons (this explains why metals conduct electricity)

16. Properties of Metals Metals are easily bent, rolled into sheets (malleable) and drawn into wires (ductile). The mobile electrons will shift to adjust to new arrangements of its positive ions. They act as the "glue".

17. Ionic VS Covalent bonding